open header?
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Joined: Oct 2007
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From: pa
HELP!!!!! OPEN HEADER PROBLEM?
im going to the track and want to see how it will run with open header.... some people say you need the back pressure but ive seen a few hondas run awesome without it. but myt main question is anyone who has done or has an open header.... do you know how much hp you gain? and if your running rich what will happen then, and do you notice a pull in power?
Modified by mck52689 at 9:53 AM 10/20/2007
Modified by mck52689 at 9:53 AM 10/20/2007
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Joined: Jan 2004
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From: Locash
Re: HELP!!!!! OPEN HEADER PROBLEM? (mck52689)
It's going to run horrible.
You never need/want backpressure. You want scavenging. One cylinder fires at a time. After it fires, the exhaust valve opens up and the exhaust shoots out (positive pressure followed by negative pressure). The intake valve is slightly open at the same time (overlap). Basically you want the vacuum created by one cylinder's exhaust pulse to pull incoming air into the next cylinder.
Another part of the equation is that the shorter the exhaust length, the higher the peak hp moves in the power band. Open header theoretically moves the peak hp in the 20,000+ RPM range.
People take these ideas from old domestic high displacement cars. Domestic cars are so poorly engineered that you can make a lot of power just by getting out of the way of the airflow. Hondas/Acuras are precision engineered to make the most power out of the least displacement. Changing things w/out knowing what you're doing screws things up and you more often lose power.
You run rich to keep your engine safe from detonation under high load and RPM. But you're compromising power for safety. In many cases, running somewhat lean gives you the best power, but this is just a generalization to demonstrate my point.
Running open header could also burn a valve. Have fun.
You never need/want backpressure. You want scavenging. One cylinder fires at a time. After it fires, the exhaust valve opens up and the exhaust shoots out (positive pressure followed by negative pressure). The intake valve is slightly open at the same time (overlap). Basically you want the vacuum created by one cylinder's exhaust pulse to pull incoming air into the next cylinder.
Another part of the equation is that the shorter the exhaust length, the higher the peak hp moves in the power band. Open header theoretically moves the peak hp in the 20,000+ RPM range.
People take these ideas from old domestic high displacement cars. Domestic cars are so poorly engineered that you can make a lot of power just by getting out of the way of the airflow. Hondas/Acuras are precision engineered to make the most power out of the least displacement. Changing things w/out knowing what you're doing screws things up and you more often lose power.
You run rich to keep your engine safe from detonation under high load and RPM. But you're compromising power for safety. In many cases, running somewhat lean gives you the best power, but this is just a generalization to demonstrate my point.
Running open header could also burn a valve. Have fun.
Thread Starter
Joined: Oct 2007
Posts: 45
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From: pa
Re: HELP!!!!! OPEN HEADER PROBLEM? (suspendedHatch)
alright i think i made my mind up after that haha... idk im broke right now and im just trying to see my options... also the idiot before me had the clutch pedal raised way up there and it sucks driving it... any one know how to change the height and engagement?
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